In the above expression, we assume that the turnover time of the smallest eddies are negligible compared with
that of the largest eddy at \(L\) .
The timescale of nonlinear dynamo is much longer than the turbulent eddy turnover time at \(L\) 
because of its inefficient dynamo growth.
The relatively long timescale of the nonlinear dynamo and its low efficiency
indicate that only a small fraction of turbulent energy contributes to the growth of magnetic energy.
This result is also consistent with that in dynamo simulations
in a cosmological context
[1]}, [2]}, [3]}
and in supernova remnants (see Section REF ).
